Tokin Corporation

Masafumi Katsuno

Yoshiaki Fuda

Katsunori Kumasaka

Koichi Okamoto

A piezoelectric transformer (,) comprises a piezoelectric rectangular body (,) equally divided into first to fourth regions (A,, A,, A,, and A,) in a longitudinal direction. The first and the fourth regions (A,, A,) are provided with plane electrodes (,and,) as input electrodes and polarized in a thickness direction. Strip-like electrodes (,) are formed at the boundary between the remaining second and third regions (A,A,) as output electrodes. An AC input voltage having a frequency corresponding to a wavelength equal to a half of the length of the piezoelectric rectangular body is applied to the input electrodes to vibrate the piezoelectric plate in a two-wavelength resonance mode. A voltage produced by a piezoelectric effect in response to the vibration is extracted from an output terminal. The transformer is small in size, low in vibration rate and heat generation, and excellent in efficiency. As a modification, the input electrodes may be formed in two or three regions which are opposite to each other in displacement distribution in the two-wavelength resonance without being restricted to the first and the fourth regions while the output electrode is provided in another region.

Piezoelectric transformer

A piezoelectric transformer element is wrapped together with primary lead members and secondary lead members by a thin soft insulating sheet, with the primary and secondary lead members being exposed outside the wrapping sheet, so that the transformer element is small in size, and easy in handling, and mounting operation on a circuit board. The primary and secondary lead members can be formed of a flexible flat cable. In an electric power supply device using the piezoelectric transformer element, the transformer element, and the flexible flat cable are wrapped by the wrapping sheet together with a portion of a circuit board on which the transformer element and other circuit elements are mounted.

Growing community of inventors

Sendai, Japan

Masafumi Katsuno